In recent redundant arrays of inexpensive disks (RAID) controllers, the numbers of parts used therein have been continuously increasing, and the configurations thereof have been becoming more complex. In particular, in an enterprise class RAID controller, redundancy of communication paths between the controller and storage devices is achieved and a plurality of relay nodes such as routers are implemented, resulting in a complex configuration. Approaches for identifying a fault location, which is a cause of occurrence of an error in access operation to a storage device, in a RAID controller having such a configuration are known.
For example, an approach in which an error point value is added for a storage device in which an error has occurred, and a storage device whose error point values have reached a threshold is identified as a fault location is known. In this approach, when a predetermined error monitoring period has elapsed, the error point values are reset.
Related techniques are disclosed in, for example, Japanese Laid-open Patent Publication No. 2009-282848, Japanese Laid-open Patent Publication No. 2009-170034, Japanese Laid-open Patent Publication No. 11-353819, and Japanese Laid-open Patent Publication No. 1-271828.
In the aforementioned approach for identifying a fault location, however, there is a problem in that any storage device may be merely identified as a fault location, and a control module (CM) or a router is not identified when the CM or the router is a fault location. There is another problem in that if the error point values at a plurality of error occurrence locations are the same, a fault location is not identified.